immune system exam style

describe how phagocytosis of a virus leads to presentation of its antigens

1.phagocyte engulfs pathogen

2.forms phagosome vesicle

3.lysosomes release lysozymes which hydrolyse the pathogen

4.antigen is presented on cell surface membrane

describe how presentation of a virus antigen leads to secretion of antibody

1. B cell is activated by T cell to divide by mitosis to give clone of plasma cell

2.plasma cells secrete specific antibody

3.antibody destroys antigen on pathogen

why wasn't a placebo given

not ethical

what is an antibody

protein with specific binding sites synthesised by b-cells.

describe how antibody gene could be isolated

1.antibody is located using gene probe

2.cut using restriction enzyme

3.at specific base pairs

4.leaving sticky ends unpaired

taking antibodies from plants= not a long term response. why

person is not making its own antibodies

why should people be vaccinated against influenzas each year

1,different types of viruss each year

2.memory cells are rapidly destroyed

describe how presentation of a virus antigen leads to the secretion of an antibody against this virus antigen

1.b cells activated by t cells to divide by mitosis and produce clones of plasma cells

2.plasma cells produce and secrete specific antibodies

3.antibody destroys the amtigens on the pathogen

describe how the antibody gene could be isolated from an animal cell

1.antibody gene is located using gene probe

2.cut using restriction enzyme at specific base pairs

3.leaving sticky ends unpaired

why should people be vaccinated by influenza virus each year

1. there are different types of viruses each year

2.memory cells are rapidly destroyed

This test only detects the presence of HIV antibodies. Give two reasons why it cannot be used to find out if a person has AIDS.

1.aids related symptom's

2.no. of helper t cells

the solution will remain yellow if a person is not infected with HIV. explain why

HIV antibody is not present

so second antibody will not bind

a mother was infected with HIV and gave birth to a baby. the baby tested postivie hor hiv. this doesn't prove that the baby is infected with hiv. explain why

baby has antibodies from the mother

so solution will always turn blue

what are the 2 purposes of the control well

1.remove any unattached antigens

2.make sure that nothing else is causing colour change

each type of antibody binds specifically to 1 protein. explain why

1.proteins have specific tertiary structures

2.each antibody has specific antigen

3.each antibody forms different antibody antigen complex

explain how antibodies were produced when mice were injected with sheep red blood cells

1.antigens were recognised as foreign

2.sheep red blood cells have antibodies on c s m

3.stimulates b cells to produce antibodies

describe how phagocytosis of a virus leads to presentation of its antigens

1.phagocyte engulfs pathogen, forming phagosome vesicle

2.phagosome fuses with lysosome

3.lysosomes hydrolyse the pathogen.

4.debris is absorbed and antigen Is presented on the cell surface membrane

what is an antibody

a protein which stimulates an immune response specific to an antigen

What is an antigen?

protein recognised as foreign which produces an immune response

what is an antibody

A PROTEIN PRODUCED BY B CELLS

describe the difference between active and passive immunity (3)

1. active involves memory cells but passive doesn't

2.active is longterm because antibody is produced passive is short term because no antibody

3.active tales a long time passive is fast

describe how complementary stand of HIV is made

1.complementry nucleotides

2.join together by DNA polymerase

3.to form phosphodiester bonds